Mechanically stabilized earth (MSE) walls consist of facing elements, soil mass and reinforcement combined to form a composite solid structure. Some of the earlier reinforcement methods that are still used today, were developed in the 1960s and they are mostly used as retaining walls, berms, seawalls and bridge abutments ever since.
In a typical MSE wall, compacted granular soil is reinforced by horizontal layers of steel strips or geosynthetic materials. The use of reinforced elements significantly increases the strength of the system. Facing elements are relatively thin components, usually made out of pre-cast concrete, welded wire mesh panels or shotcrete. Their structural objective is to hold the soil between the reinforcement layers. A facing system enables the construction of a steep or even a vertical MSE wall. Soil material is also placed without a reinforcement between the stabilized zone and the natural surface of the ground. This zone is known as retained backfill.
A complete MSE wall is a gravity-based structure. It relies on its mass to bear the applied forces including lateral earth pressures, water pressures, seismic loads or loads related to human activity.
MSE walls are cost-effective structures that may withstand larger total and differential settlements compared to concrete walls. Moreover, their construction is simpler and quicker as there is no need for support structures (e.g. scaffoldings) and curing time. They also exhibit high resistance in continuous and dynamic loads (e.g. earthquakes).Regarding the downsides of MSE construction, the wall must obtain a minimum width in order to acquire adequate stability. Moreover, the reinforced soil mass must consist of granular material which may be costly if it is not readily available. Finally, the reinforced component must be designed to withstand erosion and corrosion processes which can highly deteriorate the mechanical behavior of the composite structure.